The present invention relates to an agricultural tillage apparatus; and more particularly, it relates to a tillage apparatus providing independent depth adjustment of ground working tools carried thereon.
Efficient farming requires a limited number of passes over the farm land in order to reduce man hours on the field and maximize the work done with a given amount of fuel. In order to combine various operations within one-pass over the field, differing types of ground working tools are mounted on the implement for simultaneous use as the implement travels over the field. For example, two operations, cutting and burying trash, can be performed simultaneously by mounting coulter disks, which cut trash, to the front of an implement followed by chisel plows, which bury trash, mounted to the rear. Ideally, a farm implement would be able to accommodate the physical differences in size and shape between the differing ground working tools to allow them to be used simultaneously on the same implement.
My earlier co-pending application for a One-Pass Complete Tillage System filed Dec. 29, 1980, Ser. No. 220,419, discloses an adjustment mechanism for independently setting the depth of ground-working tools mounted on an implement frame. The adjustment mechanism, disclosed in that application, includes an actuator arm pivotally connected to the rod end of a hydraulic cylinder. The other end of the actuator arm is attached to a first or forward rock shaft which is rotatably mounted to the main frame. A link is welded at one end to rotate with the forward rock shaft and its other end is pivotally connected to a sub-frame. A parallel linkage, also controlled by the actuator arm and shaft, extends rearwardly to operate a crank mounted to a second or rear rock shaft and rear links connected to lift the rear of the sub-frame. A turnbuckle is incorporated in the parallel linkage to make minor adjustments in the operating depth of the front and rear sets of the disk blades carried on the sub-frame and to provide adjustment for wear.
The invention disclosed in my co-pending application is capable of great vertical travel because the two rock shafts and connecting turnbuckle substantially eliminate problems of lock-up or jamming of the pivoting link means, by applying rotational forces symmetrically above and below the link means. Thus, the disclosed invention of my co-pending application is capable of rotation of 150 degrees or more. However, such a degree of vertical travel is not always necessary, and a simpler less expensive construction is desirable.